Design and Modeling of an Integrated Micro-Transformer in a Flyback Converter

This paper presents the design and modeling of a square micro-transformer for its integration in a flyback converter. From the specifications of the switching power supply, we determined the geometric parameters of this micro-transformer. The π-electrical model of this micro-transformer highlights all parasitic effects generated by stacking of different material layers and permits to calculate the technological parameters by using the S-parameters. A good dimensioning of the geometrical parameters reduces efficiently the energy losses in the micro-transformer and permits to reach the desirable value of the converter output voltage. We have also simulated the electromagnetic effects with the help of the software FEMLAB3.1 in two cases. The first case, without ferromagnetic core, the second case with ferromagnetic core, in order to choose the micro-transformer that has better electromagnetic compatibility with the vicinity components. To validate dimensioning of the geometrical and technological parameters, we have simulated with the help of the software PSIM6.0, the equivalent electrical circuit of the converter containing the electrical circuit of the dimensioned planar micro-transformer

Design and Modeling of an Integrated Inductor in a Buck Converter DC-DC

This paper presents the design and modeling of a square inductor for its integration in Buck converter DC-DC. The first, we calculate the value of inductance. The second, we descript our inductor; dimensioning and electrical model. A buck micro converter schematic simulation coupled with ideal and integrated inductor was presented. This conceptual model of the buck is best understood in terms of the relation between current and voltage of the inductor. Finely, we have simulated the electromagnetic effects in two cases. The first case, an inductor in the air, the second case with substrate. Our geometry is created en 3D space dimension

Volvulus du grêle sur mésentère commun incomplet une redoutable complication rare chez l’adulte: à propos de 1 cas

Le mésentère commun résulte d'une anomalie de rotation du tube digestif. Il est caractérisé par la persistance d'une disposition anatomique embryonnaire secondaire à une anomalie de rotation de l'anse ombilicale primitive, constituant ainsi un méso commun à toute l'anse intestinale etune racine du mésentère extrêmement courte. Cette insuffisance de rotation est le plus souvent associée à un défaut d'accolement. Ces  anomalies de rotation intestinale peuvent aboutir à des complications redoutables parfois mortelles, qui surviennent généralement au cours de la période néonatale où à l'âge pédiatrique. On estime que la prévalence de ces malformations congénitales à l'âge adulte est de l'ordre de 0,2% à 0,5% âge auquel elles demeurent très souvent asymptomatiques et donc non diagnostiquées. Le diagnostic de volvulus total du grêle peut se faire dans des circonstances très variées: en urgence devant un tableau  d'occlusion intestinale aiguë, voire un état de choc pouvant conduire au décès, devant un tableau de douleurs abdominales répétées plus ou moins associées à des troubles du transit. Nous rapportons l'observation d'un patient de 18 ans admis pour volvulus total du grêle sur mésentère commun incomplet chez qui l'évolution était favorable

Time variations in the deep underground muon flux measured by MACRO

More than 30 million of high-energy muons collected with the MACRO detector at the underground Gran Sasso Laboratory have been used to search for flux variations of different natures. Two kinds of studies were carried out: search for periodic variations and for the occurrence of clusters of events. Different analysis methods, including Lomb-Scargle spectral analysis and Scan Test statistics have been applied to the data.Comment: 6 pages, 4 EPS figures. Talk given at the 29th ICRC, Pune, India, 3-10 August 200

Time variations in the deep underground muon flux

More than 35 million high-energy muons collected with the MACRO detector at the underground Gran Sasso Laboratory have been used to search for flux variations of different nature. Two kinds of studies were carried out: a search for the occurrence of clusters of events and a search for periodic variations. Different analysis methods, including the Scan Statistics test and the Lomb-Scargle spectral analysis have been applied to the data.Comment: 7 pages, 5 figures, accepted by EP

Design and Modeling of an Integrated Inductor in a Buck Converter DC-DC

This paper presents the design and modeling of a square inductor for its integration in Buck converter DC-DC. The first, we calculate the value of inductance. The second, we descript our inductor; dimensioning and electrical model. A buck micro converter schematic simulation coupled with ideal and integrated inductor was presented. This conceptual model of the buck is best understood in terms of the relation between current and voltage of the inductor. Finely, we have simulated the electromagnetic effects in two cases. The first case, an inductor in the air, the second case with substrate. Our geometry is created en 3D space dimension

Microclimat sous bâche à plat et son impact sur une culture de pomme de terre

Deux traitements ont été effectués dans un dispositif en blocs aléatoires complets avec quatre répétitions. Le premier sans bâche sert de témoin et le second utilise la bâche à plat comme couverture de la culture. La bâche en film polyéthylène perforé a été installée quinze jours après la plantation d’une culture de pomme de terre (Solanum tuberosum cv. Nicola) ayant reçu un traitement préventif contre le mildiou. La bâche a été retirée juste avant la récolte de la pomme de terre. Sous bâche à plat, les températures et les hygrométries de l’air ainsi que les températures du sol ont été supérieures à celles de l’extérieur. Les gouttelettes de condensation formées sous bâche ont réduit considérablement la transmission lumineuse. Les résultats agronomiques sont, par conséquent, affectés par ces conditions climatiques. Une nette amélioration de la croissance végétative de la pomme de terre a été observée sous bâche, mais l’attaque du mildiou a été plus importante sous bâche à plat que dans les parcelles témoins non couvertes qui ont été bien traitées. Ceci a affecté le rendement de pomme de terre sous bâche qui a enregistré une perte de 23% par rapport au témoin non couvert

Nuclear Track Detectors. Searches for Exotic Particles

We used Nuclear Track Detectors (NTD) CR39 and Makrofol for many purposes: i) Exposures at the SPS and at lower energy accelerator heavy ion beams for calibration purposes and for fragmentation studies. ii) Searches for GUT and Intermediate Mass Magnetic Monopoles (IMM), nuclearites, Q-balls and strangelets in the cosmic radiation. The MACRO experiment in the Gran Sasso underground lab, with ~1000 m^2 of CR39 detectors (plus scintillators and streamer tubes), established an upper limit for superheavy GUT poles at the level of 1.4x10^-16 cm^-2 s^-1 sr^-1 for 4x10^-5 <beta<1. The SLIM experiment at the high altitude Chacaltaya lab (5230 m a.s.l.), using 427 m^2 of CR39 detectors exposed for 4.22 y, gave an upper limit for IMMs of ~1.3x10^-15 cm^-2 s^-1 sr^-1. The experiments yielded interesting upper limits also on the fluxes of the other mentioned exotic particles. iii) Environmental studies, radiation monitoring, neutron dosimetry.Comment: Talk given at "New Trends In High-Energy Physics" (experiment, phenomenology, theory) Yalta, Crimea, Ukraine, September 27-October 4, 200

Bulk Etch Rate Measurements and Calibrations of Plastic Nuclear Track Detectors

New calibrations of CR39 and Makrofol nuclear track detectors have been obtained using 158 A GeV Pb (82+) and In (49+) ions; a new method for the bulk etch rate determination, using both cone height and base diameter measurements was developed. The CR39 charge resolution based on the etch-pit base area measurement is adequate to identify nuclear fragments in the interval 7 <= Z/beta <= 49. For CR39 the detection threshold is at REL~50 MeV cm^2/g, corresponding to a nuclear fragment with Z/beta~7. Base cone area distributions for Makrofol foils exposed to Pb (82+) ions have shown for the first time all peaks due to nuclear fragments with Z > 50; the distribution of the etched cone heights shows well separated individual peaks for Z/beta = 78 - 83 (charge pickup). The Makrofol detection threshold is at REL 2700 MeV cm^2/g, corresponding to a nuclear fragment with Z/beta~50.Comment: 11 pages, 5 EPS figures. Submitted to Nucl. Instr. Meth.